The overall goal is to continue the analysis of the Drosophila circadian system using genetic and molecular approaches. The clock in Drosophila is known to be composed of a feedback loop generated through the coordinated action of clock genes- period (per), timeless (tim), Clock (Clk), cycle (cyc), double-time (dbt). All of these genes are conserved in mammals and function in similar, if not identical, ways to regulate mammalian circadian rhythms. This application seeks to determine the role of new genes/mutations recently isolated in the PI's laboratory and to isolate additional genes through microarray technology. In addition, a ds-RNA-based method will be used to reduce activity of clock and putative clock genes in a tissue-specific manner.